This invention relates to an improved self-propelled mower and, in particular, to a sulky-type riding mower which allows the operator to raise and lower the power deck without releasing the steering yoke of the machine.
Self-equipped, sulky-type riding mowers have been known and used in the art for some time. In this type of machine, the operator is seated upon a riding unit behind the drive axle while power related equipment, such as the motor and cutting blade assemblies, is mounted upon a power deck that extends forwardly from the axle. The power deck is normally permitted to swing freely about the axle so that it can ride over the ground upon idler wheels in response to changes in terrain. The riding unit is also pivotally attached to the power deck to further enhance the machine's ability to operate in rough or undulating terrain. The sulky-type machines found in the prior art have two disadvantages. The first involves their lack of traction when operating on relatively steep inclines or on wet or slippery surfaces. This lack of traction is generally attributed to the fact that a good deal of the machine's total weight is distributed in front of or in back of the drive axle. The second difficulty associated with this type of mower relates to problems involved with servicing the cutter assemblies which are typically mounted beneath the power deck.
In U.S. Pat. No. 4,487,046 to Scag, there is disclosed a sulky-type mower that is equipped with a hand operated winch for raising and lowering the power deck about the drive axle. The winch is situated beneath the operator's seat on the riding unit. A cable is wrapped around the winch drum and passes under an idler sheave mounted below the power deck. The end of the cable, in turn, is passed upwardly around the sheave and anchored in the deck. Winding the cable about the drum pulls the power deck around the axle to raise the cutter assembly above the ground.
In the event the Scag machine loses traction while in use, the operator can crank the power deck to an elevated position to place added weight directly over the drive axle. This, under most conditions, will increase traction to the wheels and help the operator traverse difficult sections of terrain. As can be seen, however, in order to raise the deck, the operator must release the steering yoke with at least one arm and reach under the seat to engage the crank. While in a bent over position, the operator must perform the rather arduous task of winding the crank the necessary number of turns to complete the lifting operation. If the machine is in motion, the operator can very easily lose control and have an accident. Similarly, reaching under the seat and operating the winch can unbalance the machine and may cause it to tip, particularly when it is operating upon a slope. Cranking the power deck up and down repeatedly can fatigue the operator thus impairing his ability to safely control the machine.
The Scag winching system can be used to elevate the cutting assemblies when these units have to be serviced. However, as is the case with most dependent cable systems, the cable can become frayed or damaged with use to a point where it will break when placed under load. The Scag cable is completely unprotected and thus exposed to the elements. The cable hangs down beneath the machine where it can pick up moisture and highly corrosive chemical fertilizers that are used widely on lawns, highway aprons and the like. A cable under these conditions, unless made of special materials, can rapidly corrode thus increasing the danger of its breaking when placed under load.
Lastly, in order to allow the power deck to move freely up and down as it moves over the ground, the Scag cable is slackened when not actually lifting the deck. This unwanted slack can foul on foreign objects, such as sticks and branches passing beneath the machine, thus rendering the winch inoperative. The slackened cable can also, under certain conditions, move off the idler sheave again adversely effecting the operation of the winch. The operator must stop the machine and dismount in order to clear the winch mechanism which, of course, wastes a good deal of time and effort.